This invention relates to liquid ring pumps, and more particularly to reducing cavitation and its associated operating noise in liquid ring pumps, especially those having conical port members.
A typical liquid ring pump having conical port members is shown in Adams U.S. Pat. No. 3,289,918. Although the port members in pumps of the type shown in the Adams patent are actually frusto-conical, those skilled in the art usually refer to such port members as conical, and that terminology is also sometimes employed herein.
Cavitation sometimes occurs in conically ported liquid ring pumps, particularly those which are operated at high speeds and/or at low intake pressures (i.e., intake pressures near zero absolute pressure). Cavitation is believed to be caused by the sudden collapse or implosion of vapor bubbles in the pumping liquid (usually water) which constitutes the liquid ring. Vapor bubbles may be formed on the intake side of the pump and carried over to the compression side of the pump where they suddenly collapse as they approach the rotor or port member. Vapor bubbles may also be formed on the compression side of the pump where the pumping liquid approaches the rotor hub and port member and is therefore abruptly redirected. The after-effects of the sudden collapse of these vapor bubbles may be audible outside the pump and may undesirably or objectionably contribute to the operating noise level of the pump.
It is therefore an object of this invention to reduce cavitation in liquid ring pumps having conical port members.
It is another object of this invention to reduce the operating noise levels of liquid ring pumps having conical port members by reducing the noise associated with cavitation in the pumps.